The present invention includes a water control valve as an integral part and functions as a water conservation device by turning a lawn sprinkler system on only when necessary. A humidity sensitive element is located in a chamber which is positioned partially below ground level. Diffusion ports maintain the humidity inside the chamber at a level which depends on ambient humidity and on the amount of moisture in the soil. The sensitive element shrinks with reductions in humidity inside the chamber, releases a spring loaded mechanism which opens the water control valve, and thereby turns on the sprinkler system. The sensing element responds to moisture increases caused by on states of the sprinkler system.
Water flowing through the valve rotates an impeller which is coupled to a reduction gear mechanism. With the completion of a fixed number of rotations of the impeller corresponding to a fixed volume of water flow, the reduction gear mechanism resets the spring loaded opening mechanism and closes the valve. The valve remains closed until the humidity sensitive element triggers another on cycle.
The present invention is an improvement over conventional sprinkler control systems which utilize electronic techniques for sensing moisture in that it does not require an electrical power source. Because of this, it can operate under specialized conditions. This includes functioning as an integral part of a lawn sprinkler. This type of sprinkler could be attached to the exit end of a water hose and could control itself with no additional installation requirements.